1. Field of the Invention
This invention pertains to the rotational bearing and gearing of a driveshaft for an impact printer. More specifically, it pertains to the rotational bearing and gearing of a square cross section driveshaft for driving the paper feed tractors of an impact printer.
2. Description of the Prior Art
In the past, typical impact printers of the type utilizing wire matrix printheads, incorporate a square cross section driveshaft for engaging paper feed tractors for automatic paper feeding. These prior art printers have typically incorporated square drive shafts with each end turned down into a circular shape for easy rotation within a bearing in the sidewalls of the frame of the printer assembly. It has also been common practice to form a groove in the turned down, circular cross section ends for a retaining ring.
Forming a circular cross section at the end of the square shaft is a relatively expensive procedure and forming grooves for retaining rings adds still more expense. The additional bearings also add expense. In this preferred embodiment, the use of a fiberglass reinforced polycarbonate material for forming a bushing assembly, a gear and hub assembly, and a pair of bracket assemblies dramatically reduces the cost of manufacture and the cost of assembly. The bracket assemblies are identical, and the bushing assembly and hub and gear assembly each have square sockets for receiving the square ends of the drive shaft. This apparatus precludes the requirement for turning down the ends of the shaft and/or providing grooves and retaining rings.